The insect-trapping movement of the plant Dionaea muscipula (Venus's fly-trap) is mediated by the stimulation of mechanosensory hairs located on the surface of the trap. It is known that stimulation of the hairs is followed by action potentials which are propagated over the surface of the trap. It has been reported that action potentials always precede trap closure. The occurrence of non-propag...

Tools for assorting and classifying neuronal action potentials can be either on-line or off-line. Here we examine on-line tools. We concentrate on an analysis of insect action potentials by using a DSP-based multi spike detector (MSD by Alpha Omega Engineering). The MSD software is a modular program which is user-friendly and has optimal speed. In the action potential analysis neural firings ar...

Layer V pyramidal cells of the somatosensory cortex operate with two spike initiation zones. Subthreshold depolarizations are strongly attenuated along the apical dendrite linking the somatic and distal dendritic spike initiation zones. Sodium action potentials, on the other hand, are actively back-propagating from the axon hillock into the apical tuft. There they can interact with local excita...

We studied the ability of typical unmyelinated cortical axons to conduct action potentials at fever-like temperatures because fever often gives CNS symptoms. We investigated such axons in cerebellar and hippocampal slices from 10 to 25 days old rats at temperatures between 30 and 43°C. By recording with two electrodes along axonal pathways, we confirmed that the axons were able to initiate acti...

; Plants respond to various abiotic stimuli by activation and propagation of fast electrical signals, action potentials. To resolve the temporal increase in cytosolic Ca during the action potentials of higher plants, we regenerated transgenic potato plants that expressed the Ca photoprotein apoaequorin. These genetically engineered potato plants were used for simultaneous measurements of transi...

During low-frequency firing, action potentials actively invade the dendrites of CA1 pyramidal neurons. At higher firing rates, however, activity-dependent processes result in the attenuation of back-propagating action potentials, and propagation failures occur at some dendritic branch points. We tested two major hypotheses related to this activity-dependent attenuation of back-propagating actio...

The secretory cells of the salivary glands of the snail, Helisoma trivolvis, exhibit regenerative, overshooting action potentials whose ampliture may exceed 100 mV. The salivary glands consist of paired, tubular, epithelial structures with acinar outpocketings. The secretory cells display extensive electrical coupling which allows action potentials to propagate along the glandular epithelium. S...

1. The ionic dependence of action potentials evoked in giant smooth muscle fibres isolated by enzymatic digestion from the body wall of the marine invertebrate Beroe ovata (Ctenophora) has been investigated using conventional electrophysiological techniques. 2. Differences were observed in the two fibre types studied. The resting membrane potential was —60 ± 135 mV (JV = 25) in longitudinal mus...

The duration of action potentials from single nodes of Ranvier can be increased by several methods. Extraction of water from the node (e.g. by 2 to 3 M glycerin) causes increased durations up to 1000 msec. 1 to 5 min. after application of the glycerin the duration of the action potential again decreases to the normal value. Another type of prolonged action potential can be observed in solutions...